This invention relates in general to the construction of probes for measuring heat transfer of blood circulation of living tissues and, in particular, to a new and useful probe, including a probe support having a plurality of alternately arranged layers of thermoelectric conductor material and insulation formed around the support and forming two oppositely connected thermocouples, each including an outwardly extending layer of a thermoelectric material and a common connecting layer of another thermoelectric material, one of which is heated and arranged in the range of the probe tip or surface, and the other is unheated and arranged at a spaced location from the probe tip.